Stroke Volume Calculation by Esophageal Doppler Integrates Velocity Over Time and Multiplies This “Area Under The Curve” by the Cross Sectional Area of the Aorta
Bibliographic record
Abstract
To the Editor: In our recent review1 we wish to acknowledge an error that was astutely observed by Dr. Archer. In describing the calculation of stroke volume by means of esophageal Doppler, we state that the area under the curve of the velocity-time graph “is computed mathematically as the integral of the derivative of velocity over time (dV/dt) from T0 to T1 (where T0 is the start of aortic blood flow and T1 is the end of flow).” This is not accurate. The area under the curve for the velocity-time graph should be described as the integral of the velocity curve over time, not the integral of its derivative. The area under this curve is the distance traveled by blood during systole, also called the stroke distance, measured in cm. Stroke volume is then obtained by multiplying stroke distance by the cross sectional area of aorta (cm2) to obtain stroke volume (cm3). We thank Dr. Archer for pointing out this error and apologize for any confusion this may have caused. Thomas L. Archer, MD, MBA University of California San Diego, California [email protected] Duane J. Funk, MD, FRCP(C) University of Manitoba Winnipeg, Manitoba, Canada Eugene Moretti, MD Tong J. Gan, MD, FRCA Department of Anesthesia Duke University Medical Center Durham, North Carolina
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".